Materials for organic electroluminescent devices

ABSTRACT

The present invention relates to compounds of the formula (1) which are suitable for use in electronic devices, in particular organic electroluminescent devices.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 13/636,752, filed Sep. 24, 2012, which claims benefit ofnational stage application (under 35 U.S.C. §371) of PCT/EP2011/000944,filed Feb. 25, 2011, which claims benefit of German application 10 2010012 738.8, filed Mar. 25, 2010.

The present invention relates to materials for use in electronicdevices, in particular in organic electroluminescent devices.

The structure of organic electroluminescent devices (OLEDs) in whichorganic semiconductors are employed as functional materials isdescribed, for example, in U.S. Pat. No. 4,539,507, U.S. Pat. No.5,151,629, EP 0676461 and WO 98/27136. The emitting materials employedhere are increasingly organometallic complexes which exhibitphosphorescence instead of fluorescence (M. A. Baldo et al., Appl. Phys.Lett. 1999, 75, 4-6). For quantum-mechanical reasons, an up to four-foldincrease in energy and power efficiency is possible using organometalliccompounds as phosphorescent emitters. In general, however, there isstill a need for improvement in OLEDs, in particular also in OLEDs whichexhibit triplet emission (phosphorescence), for example with respect toefficiency, operating voltage and lifetime. This applies, in particular,to OLEDs which emit in the relatively short-wave region, for examplegreen.

The properties of phosphorescent OLEDs are determined not only by thetriplet emitters employed. In particular, the other materials used, suchas matrix materials, hole-blocking materials, electron-transportmaterials, hole-transport materials and electron- or exciton-blockingmaterials, are also of particular importance here. Improvements in thesematerials can thus also result in significant improvements in the OLEDproperties. There is also still a need for improvement in thesematerials for fluorescent OLEDs.

In accordance with the prior art, ketones (for example in accordancewith WO 2004/093207 or WO 2010/006680) or phosphine oxides (for examplein accordance with WO 2005/003253), inter alia, are used as matrixmaterials for phosphorescent emitters. However, there is still a needfor improvement on use of these matrix materials as in the case of othermatrix materials, in particular with respect to the efficiency andlifetime of the device.

In accordance with the prior art, carbazole derivatives, for example inaccordance with WO 2005/039246, US 2005/0069729, JP 2004/288381, EP1205527 or WO 2008/086851, and indolocarbazole derivatives, for examplein accordance with WO 2007/063754 or WO 2008/056746, are furthermoreemployed as matrix materials for phosphorescent emitters in organicelectroluminescent devices. These have the disadvantage that they arefrequently very oxidation-sensitive, which impairs the preparation,purification and storage of the materials and the long-term stability ofsolutions comprising the materials. Further improvements are desirablehere, likewise with respect to the efficiency, lifetime and thermalstability of the materials.

The object of the present invention is the provision of compounds whichare suitable for use in a fluorescent or phosphorescent OLED, inparticular a phosphorescent OLED, for example as matrix material or ashole-transport/electron-blocking material or exciton-blocking materialor as electron-transport or hole-blocking material. In particular, theobject of the present invention is to provide matrix materials which aresuitable for green- and red-, but also for blue-phosphorescent OLEDs.

Surprisingly, it has been found that the compounds described in greaterdetail below achieve this object and result in significant improvementsin the organic electroluminescent device, in particular with respect tothe lifetime, efficiency and operating voltage. This applies, inparticular, to red- and green-phosphorescent electroluminescent devices,in particular on use of the compounds according to the invention asmatrix material. The materials according to the invention arefurthermore distinguished by improved oxidation stability in solutionand by high temperature stability. The present invention thereforerelates to these materials and to organic electroluminescent deviceswhich comprise compounds of this type.

The present invention relates to a compound of the following formula(1):

where the following applies to the symbols and indices used:

-   X is C═O, C(R)₂, NR, O, S, C═S, C═NR, C═C(R)₂, Si(R)₂, BR, PR,    P(═O)R, SO or SO₂;-   Y is, identically or differently, W, as defined below, or is NR, O    or S, with the proviso that Y═C if a group E is bonded to the group    Y;-   W is on each occurrence, identically or differently, CR or N, with    the proviso that not more than three groups W in a ring stand for N,    and with the further proviso that W═C if a group E is bonded to this    group W;-   Z is, identically or differently on each occurrence, CR or N; or two    adjacent groups Z stand for a group of the formula (2)

-   -   in which the dashed bonds indicate the linking of this unit;

-   E is, identically or differently on each occurrence, a single bond,    C(R)₂, NR, O, S, C═O, C═S, C═NR, C═C(R)₂, Si(R)₂, BR, PR, P(═O)R, SO    or SO₂;

-   Ar is, together with the group Y and the two carbon atoms, an aryl    or heteroaryl group having 5 to 30 aromatic ring atoms, which may be    substituted by one or more radicals R;

-   A is R if m=n=0, and is an aryl or heteroaryl group having 5 to 30    aromatic ring atoms, which may in each case be substituted by R, or    a group —CR═CR—, —CR═N— or —N═N— if an index m or n=1 and the other    index m or n=0, or is an aryl or heteroaryl group having 5 to 30    aromatic ring atoms, which may in each case be substituted by R, if    the indices m=n=1;

-   R is selected on each occurrence, identically or differently, from    the group consisting of H, D, F, Cl, Br, I, CN, NO₂, N(Ar¹)₂,    N(R¹)₂, C(═O)Ar¹, C(═O)R¹, P(═O)(Ar¹)₂, a straight-chain alkyl,    alkoxy or thioalkyl group having 1 to 40 C atoms or a branched or    cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 C atoms or an    alkenyl or alkynyl group having 2 to 40 C atoms, each of which may    be substituted by one or more radicals R¹, where one or more    non-adjacent CH₂ groups may be replaced by R¹C═CR¹, C≡C, Si(R¹)₂,    Ge(R¹)₂, Sn(R¹)₂, C═O, C═S, C═Se, C═NR¹, P(═O)(R¹), SO, SO₂, NR¹, O,    S or CONR¹ and where one or more H atoms may be replaced by D, F,    Cl, Br, I, CN or NO₂, an aromatic or heteroaromatic ring system    having 5 to 80, preferably 5 to 60, aromatic ring atoms, which may    in each case be substituted by one or more radicals R¹, an aryloxy    or heteroaryloxy group having 5 to 60 aromatic ring atoms, which may    be substituted by one or more radicals R¹, or a combination of these    systems, where two or more adjacent substituents R may optionally    form a monocydic or polycyclic, aliphatic, aromatic or    heteroaromatic ring system, which may be substituted by one or more    radicals R¹;

-   R¹ is selected on each occurrence, identically or differently, from    the group consisting of H, D, F, Cl, Br, I, CN, NO₂, N(Ar¹)₂,    N(R²)₂, C(═O)Ar, C(═O)R², P(═O)(Ar¹)₂, a straight-chain alkyl,    alkoxy or thioalkyl group having 1 to 40 C atoms or a branched or    cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 C atoms or an    alkenyl or alkynyl group having 2 to 40 C atoms, each of which may    be substituted by one or more radicals R², where one or more    non-adjacent CH₂ groups may be replaced by R²C═CR², C≡C, Si(R²)₂,    Ge(R²)₂, Sn(R²)₂, C═O, C═S, C═Se, C═NR², P(═O)(R²), SO, SO₂, NR², O,    S or CONR² and where one or more H atoms may be replaced by D, F,    Cl, Br, I, CN or NO₂, an aromatic or heteroaromatic ring system    having 5 to 60 aromatic ring atoms, which may in each case be    substituted by one or more radicals R², an aryloxy or heteroaryloxy    group having 5 to 60 aromatic ring atoms, which may be substituted    by one or more radicals R², or a combination of these systems, where    two or more adjacent substituents R may optionally form a monocyclic    or polycyclic, aliphatic, aromatic or heteroaromatic ring system,    which may be substituted by one or more radicals R²;

-   R² is selected from the group consisting of H, D, F, CN, an    aliphatic hydrocarbon radical having 1 to 20 C atoms, an aromatic or    heteroaromatic ring system having 5 to 30 aromatic ring atoms, in    which one or more H atoms may be replaced by D, F, Cl, Br, I or CN,    where two or more adjacent substituents R² may form a mono- or    polycyclic, aliphatic, aromatic or heteroaromatic ring system with    one another;

-   Ar¹ is on each occurrence, identically or differently, an aromatic    or heteroaromatic ring system having 5-30 aromatic ring atoms, which    may be substituted by one or more non-aromatic radicals R²; two    radicals Ar¹ which are bonded to the same N atom or P atom may also    be bridged to one another here by a single bond or a bridge selected    from N(R²), C(R²)₂ or O;

-   m, n are, identically or differently on each occurrence, 0 or 1,    where, for m=0, a group R instead of the group E is bonded to A, and    where, for n=0, a group R instead of the group E is bonded to A;

-   p is 0 or 1, where, for p=0, a group R instead of the group Z═Z is    bonded to each of the carbon atom and to W, with the proviso that    p=1 if m=n=0.

An aryl group in the sense of this invention contains 6 to 60 C atoms; aheteroaryl group in the sense of this invention contains 2 to 60 C atomsand at least one heteroatom, with the proviso that the sum of C atomsand heteroatoms is at least 5. The heteroatoms are preferably selectedfrom N, O and/or S. An aryl group or heteroaryl group here is taken tomean either a simple aromatic ring, i.e. benzene, or a simpleheteroaromatic ring, for example pyridine, pyrimidine, thiophene, etc.,or a condensed (fused) aryl or heteroaryl group, for examplenaphthalene, anthracene, phenanthrene, quinoline, isoquinoline, etc.Aromatic rings linked to one another by a single bond, such as, forexample, biphenyl, are, by contrast, not referred to as an aryl orheteroaryl group, but instead as an aromatic ring system.

An aromatic ring system in the sense of this invention contains 6 to 80C atoms in the ring system. A heteroaromatic ring system in the sense ofthis invention contains 2 to 60 C atoms and at least one heteroatom inthe ring system, with the proviso that the sum of C atoms andheteroatoms is at least 5. The heteroatoms are preferably selected fromN, O and/or S. An aromatic or heteroaromatic ring system in the sense ofthis invention is intended to be taken to mean a system which does notnecessarily contain only aryl or heteroaryl groups, but instead inwhich, in addition, a plurality of aryl or heteroaryl groups may beinterrupted by a non-aromatic unit (preferably less than 10% of theatoms other than H), such as, for example, an sp³-hybridised C, N or Oatom. Thus, for example, systems such as fluorene, 9,9′-spirobifluorene,9,9-diarylfluorene, triarylamine, diaryl ether, stilbene, etc., are alsointended to be taken to be aromatic ring systems in the sense of thisinvention, as are systems in which two or more aryl groups areinterrupted, for example, by a short alkyl group.

For the purposes of the present invention, an aliphatic hydrocarbonradical or an alkyl group or an alkenyl or alkynyl group, which maytypically contain 1 to 40 or also 1 to 20 C atoms and in which, inaddition, individual H atoms or CH₂ groups may be substituted by theabove-mentioned groups, is preferably taken to mean the radicals methyl,ethyl, n-propyl, i-propyl, n-butyl, i-butyl, s-butyl, t-butyl,2-methylbutyl, n-pentyl, s-pentyl, neopentyl, cyclopentyl, n-hexyl,neohexyl, cyclohexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl,2-ethylhexyl, trifluoromethyl, pentafluoroethyl, 2,2,2-trifluoroethyl,ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl,cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl, ethynyl,propynyl, butynyl, pentynyl, hexynyl, heptynyl or octynyl. An alkoxygroup having 1 to 40 C atoms is preferably taken to mean methoxy,trifluoromethoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy,s-butoxy, t-butoxy, n-pentoxy, s-pentoxy, 2-methylbutoxy, n-hexoxy,cyclohexyloxy, n-heptoxy, cycloheptyloxy, n-octyloxy, cyclooctyloxy,2-ethylhexyloxy, pentafluoroethoxy or 2,2,2-trifluoroethoxy. A thioalkylgroup having 1 to 40 C atoms is taken to mean, in particular,methylthio, ethylthio, n-propylthio, i-propylthio, n-butylthio,i-butylthio, s-butylthio, t-butylthio, n-pentylthio, s-pentylthio,n-hexylthio, cyciohexylthio, n-heptylthio, cycloheptylthio, n-octylthio,cyclooctylthio, 2-ethylhexylthio, trifluoromethylthio,pentafluoroethylthio, 2,2,2-trifluoroethythio, ethenylthio,propenytthio, butenylthio, pentenylthio, cyclopentenylthio, hexenylthio,cyclohexenylthio, heptenylthio, cydoheptenylthio, octenylthio,cydooctenylthio, ethynylthio, propynylthio, butynylthio, pentynylthio,hexynylthio, heptynylthio or octynylthio. In general, alkyl, alkoxy orthioalkyl groups in accordance with the present invention may bestraight-chain, branched or cyclic, where one or more non-adjacent CH₂groups may be replaced by the above-mentioned groups; furthermore, oneor more H atoms may also be replaced by D, F, Cl, Br, I, CN or NO₂,preferably F, Cl or CN, furthermore preferably F or CN, particularlypreferably CN.

An aromatic or heteroaromatic ring system having 5-80 aromatic ringatoms, which may also in each case be substituted by the above-mentionedradicals R² or a hydrocarbon radical and which may be linked via anydesired positions on the aromatic or heteroaromatic ring system, istaken to mean, in particular, groups derived from benzene, naphthalene,anthracene, benzanthracene, phenanthrene, pyrene, chrysene, perylene,fluoranthene, naphthacene, pentacene, benzopyrene, biphenyl,biphenylene, terphenyl, triphenylene, fluorene, spirobifluorene,dihydrophenanthrene, dihydropyrene, tetrahydropyrene, cis- ortrans-indenofluorene, cis- or trans-indenocarbazole, cis- ortrans-indolocarbazole, truxene, isotruxene, spirotruxene,spiroisotruxene, furan, benzofuran, isobenzofuran, dibenzofuran,thiophene, benzothiophene, isobenzothiophene, dibenzothiophene, pyrrole,indole, isoindole, carbazole, pyridine, quinoline, isoquinoline,acridine, phenanthridine, benzo-5,6-quinoline, benzo-6,7-quinoline,benzo-7,8-quinoline, phenothiazine, phenoxazine, pyrazole, indazole,imidazole, benzimidazole, naphthimidazole, phenanthrimidazole,pyridimidazole, pyrazinimidazole, quinoxalinimidazole, oxazole,benzoxazole, naphthoxazole, anthroxazole, phenanthroxazole, isoxazole,1,2-thiazole, 1,3-thiazole, benzothiazole, pyridazine,hexaazatriphenylene, benzopyridazine, pyrimidine, benzopyrimidine,quinoxaline, 1,5-diazaanthracene, 2,7-diazapyrene, 2,3-diazapyrene,1,6-diazapyrene, 1,8-diazapyrene, 4,5-diazapyrene,4,5,9,10-tetraazaperylene, pyrazine, phenazine, phenoxazine,phenothiazine, fluorubin, naphthyridine, azacarbazole, benzocarboline,phenanthroline, 1,2,3-triazole, 1,2,4-triazole, benzotriazole,1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole,1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole,1,3,4-thiadiazole, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine,tetrazole, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine, 1,2,3,5-tetrazine,purine, pteridine, indolizine and benzothiadiazole or groups derivedfrom combinations of these systems.

In a preferred embodiment of the invention, X stands for C═O, CR₂, S, Oor SO₂, particularly preferably for C═O or SO₂.

In a further preferred embodiment of the invention, E stands,identically or differently on each occurrence, for a single bond, CR₂,C═O, NR, O or S, particularly preferably for a single bond, CR₂, C═O orNR, very particularly preferably for a single bond, CR₂ or C═O, inparticular for a single bond.

In yet a further preferred embodiment of the invention, the group Astands for an aryl or heteroaryl group having 5 to 16, in particular 5to 10, aromatic ring atoms, which may in each case be substituted by oneor more radicals R, or for a group of the formula —CR═CR—, —CR═N— or—N═N—.

In a particularly preferred embodiment of the invention, the group Astands for a group of the following formula (3), (4), (5) or (6):

where the dashed bond indicates the link to N, * indicates the positionof the link to E if a group E is present, and W has the meaning givenabove. W here is equal to C if a group E is bonded at this position.Furthermore, V stands for NR, O or S.

In a further preferred embodiment of the invention, the unit Z═Z in thefive-membered ring of the formula (1) stands for a group of the formula(2) given above. Furthermore, the unit Z═Z in the six-membered ring ofthe formula (1) preferably stands for —CR═CR— or —CR═N—, in particularfor —CR═CR—.

In a further preferred embodiment of the invention, the group Ar standsfor a group of one of the following formulae (7), (8), (9) or (10):

where the dashed bond indicates the link to N, # indicates the positionof the link to X, * indicates the position of the link to E if a group Eis present, and W and V have the meanings given above. W here is equalto C if a group E is bonded at this position.

In yet a further preferred embodiment of the invention, at least oneindex m or n=1. Particularly preferably, m+n=1.

In yet a further preferred embodiment of the invention, the index p=1.

In a particularly preferred embodiment of the invention, the preferencesgiven above occur simultaneously. Particular preference is thereforegiven to compounds of the formula (1) for which:

-   X is C═O, CR₂, S, O or SO₂;-   E is, identically or differently on each occurrence, a single bond,    CR₂, C═O, NR, O or S;-   A is an aryl or heteroaryl group having 5 to 16 aromatic ring atoms,    which may in each case be substituted by one or more radicals R, or    a group —CR═CR—, —CR═N— or —N═N—;-   Z═Z in the five-membered ring of the formula (1) stands for a group    of the formula (2) given above;-   Ar stands for a group of one of the following formulae (7) to (10):

-   -   where the dashed bond indicates the link to N, # indicates the        position of the link to X, * indicates the position of the link        to E if a group E is present, and W has the meaning given above;        W here is equal to C if a group E is bonded at this position;        furthermore, V stands for NR, O, S or CR₂;

-   m, n are, identically or differently on each occurrence, 0 or 1,    where at least one index m or n=1.

In a very particularly preferred embodiment of the invention, thefollowing applies to compounds of the formula (1):

-   X is C═O or SO₂;-   E is, identically or differently on each occurrence, a single bond,    CR₂, C═O or NR, preferably a single bond, CR₂ or C═O, particularly    preferably a single bond;-   A stands for a group of one of the following formulae (3) to (6);

-   -   where the dashed bond indicates the link to Y, * indicates the        position of the link to E if a group E is present, and W and V        have the meanings given above; W here is equal to C if a group E        is bonded at this position;

-   Z═Z in the five-membered ring of the formula (1) stands for a group    of the formula (2) given above and in the six-membered ring of the    formula (1) stands for CR═CR or CR═N;

-   Ar stands for a group of one of the formulae (7) to (10) given    above;

-   m, n are, identically or differently, 0 or 1, where m+n=1;

-   p is equal to 1.

Particularly preferred embodiments of the invention are thereforecompounds of the following formulae (11) to (37):

where the symbols used have the meanings given above.

In a further preferred embodiment of the compounds of the formulae (11)to (37), a total of a maximum of one symbol W or Z per ring stands for Nand the remaining symbols W and Z stand for CR. In a particularlypreferred embodiment of the invention, all symbols W and Z stand for CR.Particular preference is therefore given to the compounds of thefollowing formulae (1a) to (37a):

where the symbols used have the meanings given above.

Very particular preference is given to the compounds of the followingformulae (1 b) to (37b):

where the symbols used have the meanings given above.

Especial preference is given to the compounds of the following formulae(11c) to (37c):

where the symbols used have the meanings given above.

In the formulae (11a) to (37c), X preferably stands for C═O or SO₂.

Furthermore, in the formulae (11a) to (37c), E preferably stands forCR₂, C═O or NR.

In the formulae (11a) to (37c), it is particularly preferred for X tostand for C═O or SO₂ and at the same time for E to stand for CR₂, C═O orNR.

In a preferred embodiment of the invention, R in the formulae givenabove is selected, identically or differently on each occurrence, fromthe group consisting of H, D, F, Cl, Br, CN, N(Ar¹)₂, C(═O)Ar¹, astraight-chain alkyl or alkoxy group having 1 to 10 C atoms or abranched or cyclic alkyl or alkoxy group having 3 to 10 C atoms or analkenyl or alkynyl group having 2 to 10 C atoms, each of which may besubstituted by one or more radicals R¹, where one or more non-adjacentCH₂ groups may be replaced by O and where one or more H atoms may bereplaced by D or F, an aromatic or heteroaromatic ring system having 5to 30 aromatic ring atoms, which may in each case be substituted by oneor more radicals R¹, an aryloxy or heteroaryloxy group having 5 to 30aromatic ring atoms, which may be substituted by one or more radicalsR¹, or a combination of these systems.

In a particularly preferred embodiment of the invention, R in theformulae given above is selected, identically or differently on eachoccurrence, from the group consisting of H, D, F, Cl, Br, CN, astraight-chain alkyl group having 1 to 10 C atoms or a branched orcyclic alkyl group having 3 to 10 C atoms, each of which may besubstituted by one or more radicals R¹, where one or more H atoms may bereplaced by D or F, an aromatic or heteroaromatic ring system having 5to 18 aromatic ring atoms, which may in each case be substituted by oneor more radicals R¹, or a combination of these systems.

For compounds which are processed by vacuum evaporation, the alkylgroups preferably have not more than four C atoms, particularlypreferably not more than 1 C atom. For compounds which are processedfrom solution, compounds which are substituted by alkyl groups having upto 10 C atoms or which are substituted by oligoarylene groups, forexample ortho-, meta-, para- or branched terphenyl groups, are alsosuitable.

Examples of preferred compounds in accordance with the embodimentsindicated above or compounds as can preferably be employed in electronicdevices are the compounds of the following structures.

The compounds according to the invention can be prepared by syntheticsteps known to the person skilled in the art, as depicted schematicallyin Schemes 1 to 8. The synthesis here is carried out starting fromcis-indolocarbazole or related derivatives, the synthesis of which isknown to the person skilled in the art (for example Chemistry Letters2005, 34(11), 1500-1501; Tetrahedron Letters 2009, 50(13), 1469-1471;Khimiya Geterotsiklichenskikh Soedinenii 1985, (9), 1222-1224).

A possible synthesis here is the reaction of the cis-indolocarbazole orthe related derivative with an ortho-halobenzoic acid ester, where thehalogen is preferably iodine, in the presence of copper and a copper(I)salt, as depicted in Scheme 1.

A further possible synthesis here is the reaction of thecis-indolocarbazole or the related derivative with an ortho-halobenzoylchloride, where the halogen is preferably iodine. In a first step here,the acid chloride reacts with one of the two nitrogen atoms, and, in afurther step, the halogen reacts with the second nitrogen atom in thepresence of copper and a copper(I) salt, as depicted in Scheme 2.

An SO₂ bridge can be introduced by reacting the cis-indolocarbazole orthe related derivative with an ortho-halosulfonic acid chloride, wherethe halogen is preferably iodine. In a first step here, the sulfonicacid chloride reacts with one of the two nitrogen atoms, and, in afurther step, the halogen reacts with the second nitrogen atom in thepresence of copper and a copper(I) salt, as depicted in Scheme 3.

A CR₂ bridge can be introduced by reacting the cis-indolocarbazole orthe related derivative with an ortho-halobenzyl chloride, where thehalogen is preferably iodine. In a first step here, the benzyl chloridereacts with one of the two nitrogen atoms, and, in a further step, thehalogen reacts with the second nitrogen atom in the presence of copperand a copper(I) salt, as depicted in Scheme 4.

A phosphorus bridge can be introduced by reacting thecis-indolocarbazole or the related derivative with anortho-halophosphinyl chloride, where the halogen is preferably iodine.In a first step here, the phosphinyl chloride reacts with one of the twonitrogen atoms, and, in a further step, the halogen reacts with thesecond nitrogen atom in the presence of copper and a copper(I) salt, asdepicted in Scheme 5. A phosphine oxide bridge can be introducedanalogously by reaction with a phosphinyl oxychloride.

The synthesis of further derivatives according to the invention whichare not derived directly from the indolocarbazole, but instead whichcontain other groups E, is depicted schematically in Scheme 6 to Scheme8.

The present invention therefore furthermore relates to a process for thepreparation of a compound of the formula (1) by reaction of acis-indolocarbazole derivative with an aryl or heteroaryl derivativewhich is substituted in the ortho-positions by halogen, preferablyiodine, and an acid derivative. The acid derivative here is preferably acarboxylic acid ester, a carboxylic acid halide, a sulfonic acid halide,a phosphinyl halide or a phosphinyl oxyhalide.

The compounds according to the invention described above, in particularcompounds which are substituted by reactive leaving groups, such asbromine, iodine, chlorine, boronic acid or boronic acid ester, or byreactive, polymensable groups, such as olefins or oxetanes, can be usedas monomers for the preparation of corresponding oligomers, dendrimersor polymers. The oligomerisation or polymerisation here preferably takesplace via the halogen functionality or the boronic acid functionality orvia the polymerisable group. It is furthermore possible to crosslink thepolymers via groups of this type. The compounds and polymers accordingto the invention can be employed as a crosslinked or uncrosslinkedlayer.

The invention therefore furthermore relates to oligomers, polymers ordendrimers comprising one or more of the compounds according to theinvention indicated above, where one or more bonds are present from thecompound according to the invention to the polymer, oligomer ordendrimer. Depending on the linking of the compound according to theinvention, this therefore forms a side chain of the oligomer or polymeror is linked in the main chain. The polymers, oligomers or dendrimersmay be conjugated, partially conjugated or non-conjugated. The oligomersor polymers may be linear, branched or dendritic. The same preferencesas described above apply to the recurring units of the compoundsaccording to the invention in oligomers, dendrimers and polymers.

For the preparation of the oligomers or polymers, the monomers accordingto the invention are homopolymerised or copolymerised with furthermonomers. Preference is given to homopolymers or copolymers, where theunits of the formula (1) or the preferred embodiments mentioned aboveare present in a proportion of 0.01 to 99.9 mol %, preferably 5 to 90mol %, particularly preferably 20 to 80 mol %. Suitable and preferredcomonomers which form the polymer backbone are selected from fluorenes(for example in accordance with EP 842208 or WO 2000/22026),spirobifluorenes (for example in accordance with EP 707020, EP 894107 orWO 2006/061181), para-phenylenes (for example in accordance with WO92/18552), carbazoles (for example in accordance with WO 2004/070772 orWO 2004/113468), thiophenes (for example in accordance with EP 1028136),dihydrophenanthrenes (for example in accordance with WO 2005/014689),cis- and trans-indenofluorenes (for example in accordance with WO2004/041901 or WO 2004/113412), ketones (for example in accordance withWO 2005/040302), phenanthrenes (for example in accordance with WO2005/104264 or WO 2007/017066) or also a plurality of these units. Thepolymers, oligomers and dendrimers may also comprise further units, forexample hole-transport units, in particular those based ontriarylamines, and/or electron-transport units. In addition, thepolymers can either comprise triplet emitters in copolymerised form ormixed in as a blend. Precisely the combination of units of the formula(1) or the preferred embodiments mentioned above with triplet emittersgives particularly good results.

Furthermore, the compounds of the formula (1) or the preferredembodiments mentioned above may also be functionalised further and thusconverted into extended structures. An example which may be mentionedhere is the reaction with arylboronic acids by the Suzuki method or withprimary or secondary amines by the Hartwig-Buchwald method. Thus, thecompounds of the formula (1) or the preferred embodiments mentionedabove can also be bonded directly to phosphorescent metal complexes oralso to other metal complexes.

The compounds according to the invention are suitable for use in anelectronic device. An electronic device here is taken to mean a devicewhich comprises at least one layer which comprises at least one organiccompound. However, the component here may also comprise inorganicmaterials or also layers built up entirely from inorganic materials.

The present invention therefore furthermore relates to the use of thecompounds according to the invention mentioned above in an electronicdevice, in particular in an organic electroluminescent device.

The present invention again furthermore relates to an electronic devicecomprising at least one of the compounds according to the inventionmentioned above. The preferences stated above likewise apply to theelectronic devices.

The electronic device is preferably selected from the group consistingof organic electroluminescent devices (OLEDs), organic integratedcircuits (O-ICs), organic field-effect transistors (O-FETs), organicthin-film transistors (O-TFTs), organic light-emitting transistors(O-LETs), organic solar cells (O-SCs), organic optical detectors,organic photoreceptors, organic field-quench devices (O-FQDs),light-emitting electrochemical cells (LECs), organic laser diodes(O-lasers) and “organic plasmon emitting devices” (D. M. Koller et al.,Nature Photonics 2008, 1-4), but preferably organic electroluminescentdevices (OLEDs), particularly preferably phosphorescent OLEDs.

The organic electroluminescent device comprises a cathode, an anode andat least one emitting layer. Apart from these layers, it may alsocomprise further layers, for example in each case one or morehole-injection layers, hole-transport layers, hole-blocking layers,electron-transport layers, electron-injection layers, exciton-blockinglayers, electron-blocking layers and/or charge-generation layers. It islikewise possible for interlayers, which have, for example, anexciton-blocking function, to be introduced between two emitting layers.However, it should be pointed out that each of these layers does notnecessarily have to be present. The organic electroluminescent devicemay comprise one emitting layer or a plurality of emitting layers. If aplurality of emission layers are present, these preferably have in totala plurality of emission maxima between 380 nm and 750 nm, resultingoverall in white emission, i.e. various emitting compounds which areable to fluoresce or phosphoresce are used in the emitting layers.Particular preference is given to systems having three emitting layers,where the three layers exhibit blue, green and orange or red emission(for the basic structure see, for example, WO 2005/011013).

The compound according to the invention in accordance with theembodiments indicated above can be employed in various layers, dependingon the precise structure. Preference is given to an organicelectroluminescent device comprising a compound of the formula (1) orthe preferred embodiments mentioned above as matrix material forfluorescent or phosphorescent emitters, in particular for phosphorescentemitters, and/or in a hole-blocking layer and/or in anelectron-transport layer and/or in an electron-blocking orexciton-blocking layer and/or in a hole-transport layer, depending onthe precise substitution. The preferred embodiments indicated above alsoapply to the use of the materials in organic electronic devices.

In a further embodiment of the invention, the organic electroluminescentdevice comprises the compound of the formula (1) or the preferredembodiments mentioned above in an optical coupling-out layer. An opticalcoupling-out layer here is taken to mean a layer which is not locatedbetween the anode and cathode, but instead is applied to an electrodeoutside the actual device, for example between an electrode and asubstrate, in order to improve the optical coupling out.

In a preferred embodiment of the invention, the compound of the formula(1) or the preferred embodiments mentioned above is employed as matrixmaterial for a fluorescent or phosphorescent compound, in particular fora phosphorescent compound, in an emitting layer. The organicelectroluminescent device here may comprise one emitting layer or aplurality of emitting layers, where at least one emitting layercomprises at least one compound according to the invention as matrixmaterial.

If the compound of the formula (1) or the preferred embodimentsmentioned above is employed as matrix material for an emitting compoundin an emitting layer, it is preferably employed in combination with oneor more phosphorescent materials (triplet emitters). Phosphorescence inthe sense of this invention is taken to mean the luminescence from anexcited state of relatively high spin multiplicity, i.e. a spinstate >1, in particular from an excited triplet state. For the purposesof this application, all luminescent complexes containing transitionmetals or lanthanides, in particular all iridium, platinum and coppercomplexes, are to be regarded as phosphorescent compounds.

The mixture comprising the compound of the formula (1) or the preferredembodiments mentioned above and the emitting compound comprises between99 and 1% by vol., preferably between 98 and 10% by vol., particularlypreferably between 97 and 60% by vol., in particular between 95 and 80%by vol., of the compound of the formula (1) or the preferred embodimentsmentioned above, based on the entire mixture comprising emitter andmatrix material. Correspondingly, the mixture comprises between 1 and99% by vol., preferably between 2 and 90% by vol., particularlypreferably between 3 and 40% by vol., in particular between 5 and 20% byvol., of the emitter, based on the entire mixture comprising emitter andmatrix material.

A further preferred embodiment of the present invention is the use ofthe compound of the formula (1) or the preferred embodiments mentionedabove as matrix material for a phosphorescent emitter in combinationwith a further matrix material. Particularly suitable matrix materialswhich can be employed in combination with the compounds of the formula(1) or the preferred embodiments mentioned above are aromatic ketones,aromatic phosphine oxides or aromatic sulfoxides or sulfones, forexample in accordance with WO 2004/013080, WO 2004/093207, WO2006/005627 or WO 2010/006680, triarylamines, carbazole derivatives, forexample CBP (N,N-biscarbazolylbiphenyl) or the carbazole derivativesdisclosed in WO 2005/039246, US 2005/0069729, JP 2004/288381, EP 1205527or WO 2008/086851, indolocarbazole derivatives, for example inaccordance with WO 2007/063754 or WO 2008/056746, indenocarbazolederivatives, for example in accordance with WO 2010/136109 or theunpublished application DE 102009023155.2 or DE 102009031021.5,azacarbazole derivatives, for example in accordance with EP 1617710, EP1617711, EP 1731584, JP 2005/347160, bipolar matrix materials, forexample in accordance with WO 2007/137725, silanes, for example inaccordance with WO 2005/111172, azaboroles or boronic esters, forexample in accordance with WO 2006/117052, triazine derivatives, forexample in accordance with WO 2007/063754, WO 2008/056746, WO2010/015306 or the unpublished application DE 102009053382.6, DE102009053644.2 or DE 102009053645.0, zinc complexes, for example inaccordance with EP 652273 or WO 2009/062578, diazasilole ortetraazasilole derivatives, for example in accordance with WO2010/054729, diazaphosphole derivatives, for example in accordance withWO 2010/054730, bridged carbazole derivatives, for example in accordancewith the unpublished applications DE 102009048791.3 and DE102009053836.4. A further phosphorescent emitter which emits at shorterwavelength than the actual emitter may likewise be present in themixture as co-host.

Suitable phosphorescent compounds (=triplet emitters) are, inparticular, compounds which emit light, preferably in the visibleregion, on suitable excitation and in addition contain at least one atomhaving an atomic number greater than 20, preferably greater than 38 andless than 84, particularly preferably greater than 56 and less than 80,in particular a metal having this atomic number. The phosphorescentemitters used are preferably compounds which contain copper, molybdenum,tungsten, rhenium, ruthenium, osmium, rhodium, iridium, palladium,platinum, silver, gold or europlum, in particular compounds whichcontain iridium or platinum.

Examples of the emitters described above are revealed by theapplications WO 00/70655, WO 01/41512, WO 02/02714, WO 02/15645, EP1191613, EP 1191612, EP 1191614, WO 05/033244, WO 05/019373, US2005/0258742 and WO 2010/086089. In general, all phosphorescentcomplexes as used in accordance with the prior art for phosphorescentOLEDs and as are known to the person skilled in the art in the area oforganic electroluminescence are suitable, and the person skilled in theart will be able to use further phosphorescent complexes withoutinventive step.

In a further embodiment of the invention, the organic electroluminescentdevice according to the invention does not comprise a separatehole-injection layer and/or hole-transport layer and/or hole-blockinglayer and/or electron-transport layer, i.e. the emitting layer isdirectly adjacent to the hole-injection layer or the anode, and/or theemitting layer is directly adjacent to the electron-transport layer orthe electron-injection layer or the cathode, as described, for example,in WO 2005/053051. It is furthermore possible to use a metal complexwhich is identical or similar to the metal complex in the emitting layeras hole-transport or hole-injection material directly adjacent to theemitting layer, as described, for example, in WO 2009/030981.

In a further preferred embodiment of the invention, the compound of theformula (1) or the preferred embodiments mentioned above is employed aselectron-transport material in an electron-transport orelectron-injection layer. The emitting layer here may be fluorescent orphosphorescent. If the compound is employed as electron-transportmaterial, it may be preferred for it to be doped, for example withalkali-metal complexes, such as, for example, LiQ (lithiumhydroxyquinolinate).

In yet a further preferred embodiment of the invention, the compound ofthe formula (1) or the preferred embodiments mentioned above is employedin a hole-blocking layer. A hole-blocking layer is taken to mean a layerwhich is directly adjacent to an emitting layer on the cathode side.

It is furthermore possible to use the compound of the formula (1) or thepreferred embodiments mentioned above both in a hole-blocking layer orelectron-transport layer and as matrix in an emitting layer.

In yet a further embodiment of the invention, the compound of theformula (1) or the preferred embodiments mentioned above is employed ina hole-transport layer or in an electron-blocking layer orexciton-blocking layer.

In the further layers of the organic electroluminescent device accordingto the invention, it is possible to use all materials as usuallyemployed in accordance with the prior art. The person skilled in the artwill therefore be able, without inventive step, to employ all materialsknown for organic electroluminescent devices in combination with thecompounds of the formula (1) according to the invention or the preferredembodiments mentioned above.

Preference is furthermore given to an organic electroluminescent device,characterised in that one or more layers are applied by means of asublimation process, in which the materials are vapour-deposited invacuum sublimation units at an initial pressure of less than 10⁻⁵ mbar,preferably less than 10⁻⁶ mbar. However, it is also possible for theinitial pressure to be even lower, for example less than 10⁻⁷ mbar.

Preference is likewise given to an organic electroluminescent device,characterised in that one or more layers are applied by means of theOVPD (organic vapour phase deposition) process or with the aid ofcarriergas sublimation, in which the materials are applied at a pressurebetween 10⁻⁵ mbar and 1 bar. A special case of this process is the OVJP(organic vapour jet printing) process, in which the materials areapplied directly through a nozzle and thus structured (for example M. S.Arnold et al., Appl. Phys. Lett. 2008, 92, 053301).

Preference is furthermore given to an organic electroluminescent device,characterised in that one or more layers are produced from solution,such as, for example, by spin coating, or by means of any desiredprinting process, such as, for example, screen printing, flexographicprinting, offset printing, LITI (light induced thermal imaging, thermaltransfer printing), inkjet printing or nozzle printing. Solublecompounds, which are obtained, for example, by suitable substitution,are necessary for this purpose. These processes are also particularlysuitable for oligomers, dendrimers and polymers.

Also possible are hybrid processes, in which, for example, one or morelayers are applied from solution and one or more further layers areapplied by vapour deposition.

These processes are generally known to the person skilled in the art andcan be applied by him without inventive step to organicelectroluminescent devices comprising the compounds according to theinvention.

The compounds according to the invention and the organicelectroluminescent devices according to the invention are distinguishedby the following surprising advantages over the prior art

-   1. The compounds according to the invention or compounds of the    formula (1) or the preferred embodiments mentioned above, employed    as matrix material for fluorescent or phosphorescent emitters,    result in very high efficiencies and long lifetimes. This applies,    in particular, if the compounds are employed as matrix material for    a phosphorescent emitter.-   2. The compounds according to the invention or compounds of the    formula (1) or the preferred embodiments mentioned above are    suitable not only as matrix for red- and green-phosphorescent    compounds, but, in particular, also for blue-phosphorescent    compounds.-   3. On use as matrix material for phosphorescent compounds, very good    results are also achieved with a low emitter concentration. This is    frequently not the case with matrix materials in accordance with the    prior art, but is desirable in view of the rarity of the metals,    such as iridium or platinum, usually used in phosphorescent    compounds.-   4. In contrast to many compounds in accordance with the prior art,    which undergo partial or complete pyrolytic decomposition on    sublimation, the compounds according to the invention have high    thermal stability.-   5. The compounds according to the invention, employed in organic    electroluminescent devices, result in high efficiencies and in steep    current/voltage curves with low use voltages.-   6. The compounds according to the invention also result in very good    properties with respect to the efficiency, lifetime and operating    voltage of organic electroluminescent devices on use as    electron-transport material.

These above-mentioned advantages are not accompanied by an impairment inthe other electronic properties.

The invention is explained in greater detail by the following examples,without wishing to restrict it thereby. The person skilled in the artwill be able to use the descriptions to carry out the inventionthroughout the range disclosed and to prepare further compoundsaccording to the invention without inventive step and use them inelectronic devices or use the process according to the invention.

EXAMPLES

The following syntheses are carried out under a protective-gasatmosphere, unless indicated otherwise. The starting materials can bepurchased from ALDRICH or ABCR (palladium(II) acetate,tri-o-tolylphosphine, inorganics, solvents). The synthesis of11,12-dihydroindolo[2,3-a]-carbazole can be carried out in accordancewith the literature (Bulletin of the Chemical Society of Japan 2007, 80(6), 1199-1201). The syntheses of bisindole (Journal of OrganicChemistry 2007, 72(9), 3537-3542) and 1-bromocarbazole (Journal ofOrganic Chemistry 2001, 66(25), 8612-8615), 1-hydroxycarbazole (Journalof Organic Chemistry 1988, 53(4), 794-9),1,10-dihydropyrrolo[2,3-a]carbazole (Khimiya GeterotsiklicheskikhSoedinenii 1979, (10), 1362-6) and 1H,8H-pyrrolo[3,2-g]indole(Tetrahedron Letters 2009, 50 (13), 1469-1471) and1,8-dihydro-2,7-diphenylbenzo[2,1-b:3,4-b′]dipyrrole (TetrahedronLetters 2009, 50 (13), 1469-1471) are likewise known from theliterature.

Example 1

37.4 g (145 mmol) of 11,12-dihydroindolo[2,3-a]carbazole are added to 23ml (159.5 mmol) of methyl 2-iodobenzoate in 150 ml of di-n-butyl ether,and the solution is degassed. 10 g (158 mmol) of copper powder, 1.38 g(7 mmol) of copper(I) iodide and 22 g (159.6 mmol) of K₂CO₃ aresubsequently added to the mixture, which is then stirred at 144° C.under protective gas for 4 days. The organic phase is dried over MgSO₄,and the solvent is removed in vacuo. The residue is recrystallised fromacetone and finally sublimed in a high vacuum. Yield: 20.9 g (58.4mmol), 40% of theory, purity according to HPLC 99.9%.

Example 2

The compound is synthesised by the same procedure as Example 1 byreaction of 37.4 g (145 mmol) of 11,12-dihydroindolo[2,3-a]carbazolewith 54 g (159.5 mmol) of methyl 3-iodobiphenyl-2-carboxylate. Theresidue is recrystallised from CH₂Cl₂/isopropanol and finally sublimedin a high vacuum. Yield: 24.5 g (56 mmol), 39% of theory, purityaccording to HPLC 99.9%.

Example 3

The compound is synthesised by the same procedure as Example 1 byreaction of 37.4 g (145 mmol) of 11,12-dihydroindolo[2,3-a]carbazolewith 42 g (159.5 mmol) of methyl 3-iodothiophene-2-carboxylate. Theresidue is recrystallised from CH₂Cl₂/isopropanol and finally sublimedin a high vacuum. Yield: 22.6 g (62 mmol), 43% of theory, purityaccording to HPLC 99.9%.

Example 4

The compound is synthesised by the same procedure as Example 1 byreaction of 33.6 g (145 mmol) of bisindole with 23 ml (159.5 mmol) ofmethyl 2-iodobenzoate. The residue is recrystallised from toluene andfinally sublimed in a high vacuum. Yield: 22.4 g (66 mmol), 47% oftheory, purity according to HPLC 99.9%.

Example 5

The compound is synthesised by the same procedure as Example 1 byreaction of 44 g (145 mmol) of1,8-dihydro-2,7-diphenylbenzo[2,1-b:3,4-b′]-dipyrrole with 23 ml (159.5mmol) of methyl 2-iodobenzoate. The residue is recrystallised fromtoluene and finally sublimed in a high vacuum. Yield: 20.84 g (50 mmol),35% of theory, purity according to HPLC 99.9%.

Example 6

1st Step: 11(2-iodobenzenesulfonyl)-11,12-dihydro-11,12-diazaindeno[2,1-a]fluorene

43 g (169 mmol) of 11,12-dihydroindolo[2,3-a]carbazole are initiallyintroduced in 1000 ml of THF, and 8.9 g (223.3 mmol) of NaH (60% in oil)are added at 0° C. 24 g (80 mmol) of 2-iodobenzenesulfonyl chloride aresubsequently added to the mixture, which is then stirred at 40° C. for12 h. The organic phase is dried over MgSO₄, and the solvent is removedin vacuo. The residue is recrystallised from acetone and finallysublimed in a high vacuum. Yield: 29 g (574 mmol), 72% of theory, purityaccording to HPLC 99.9%.

2nd step

The ring closure is carried out by the same procedure as Example 1 byreaction of 46 g (145 mmol) of11-(2-iodobenzenesulfonyl)-11,12-dihydro-11,12-diazaindeno[2,1-a]fluorenewith 10 g (158 mmol) of copper powder, 1.38 g (7 mmol) of copper(I)iodide and 22 g (159.6 mmol) of K₂CO₃. The residue is recrystallisedfrom CH₂Cl₂/isopropanol and finally sublimed in a high vacuum. Yield:11.9 g (30 mmol), 38% of theory, purity according to HPLC 99.9%.

Example 7

1st Step: 9-benzenesulfonyl-1-bromo-9H-carbazole

19.6 g (80 mmol) of 1-bromocarbazole are initially introduced in 1000 mlof THF, and 8.9 g (223.3 mmol) of NaH (60% in oil) are added at 0° C. 24g (80 mmol) of 2-iodobenzenesulfonyl chloride are subsequently added tothe mixture, which is then stirred at 40° C. for 12 h. The organic phaseis dried over MgSO₄, and the solvent is removed in vacuo. The residue isrecrystallised from acetone and finally sublimed in a high vacuum.Yield: 29 g (574 mmol), 72% of theory, purity according to HPLC 99.9%.

2nd Step: methyl 9-benzenesulfonyl-9H-[1,9′]bicarbazolyl-1′-carboxylate

8.0 g (42.2 mmol) of copper(I) iodide, 11.7 ml (97.5 mmol) oftrans-cyclohexanediamine are added to a well-stirred suspension of 26.3g (117 mmol) of methyl 9H-carbazole-1-carboxylate, 45.2 g (117 mmol) of9-benzenesulfonyl-1-bromo-9H-carbazole and 416.4 g (1961 mmol) ofpotassium phosphate in 1170 ml of dioxane, and the mixture issubsequently heated under reflux for 16 h. After cooling, theprecipitated solid is filtered off with suction, washed three times with50 ml of toluene, three times with 50 ml of ethanol:water (1:1, v:v) andthree times with 100 ml of ethanol. Yield: 43 g (81 mmol), 70% oftheory.

3rd Step: methyl 9H-[1,9′]bicarbazolyl-1′-carboxylate

65 g (123 mmol) of methyl9-benzenesulfonyl-9H-[1,9′]bicarbazolyl-1′-carboxylate and 48 g (856mmol) of potassium hydroxide in 65 ml of dimethyl sulfoxide and 21 ml ofwater are heated at 60° C. for 1 h. The mixture is subsequently cooledto room temperature, neutralised using 1 M HCl solution and extractedwith dichloromethane. The solvent is evaporated in vacuo, and theresidue is purified by chromatography (heptane/ethyl acetate 10:1).Yield: 45 g (116 mmol), 95% of theory.

4th Step: cyclisation

22 g (159.6 mmol) of K₂CO₃ are added to 56.5 g (145 mmol) of methyl9H[1,9′]bicarbazolyl-1′-carboxylate in 151 ml of di-n-butyl ether, andthe mixture is stirred at 144° C. under protective gas for 4 days. Theorganic phase is dried over MgSO₄, and the solvent is removed in vacuo.The residue is recrystallised from acetone and finally sublimed in ahigh vacuum. Yield: 25 g (69.7 mmol), 49% of theory, purity according toHPLC 99.9%.

Example 8

1st Step: 2-(12H-11,12-diazaindeno[2,1-a]fluoren-11-yl)benzenethiol

25 g (96.6 mmol) of 11,12-dihydroindolo[2,3-a]carbazole are added to12.5 g (48 mmol) of 2-iodobenzenethiol in 80 ml of di-n-butyl ether, andthe solution is degassed. 6.6 g (0.105 mmol) of copper powder, 0.92 g(0.003 mmol) of copper(I) iodide and 14.6 g (106.6 mmol) of K₂CO₃ aresubsequently added to the mixture, which is then stirred at 144° C.under protective gas for 4 days. The organic phase is dried over MgSO₄,and the solvent is removed in vacuo. The residue is recrystallised fromacetone and finally sublimed in a high vacuum. Yield: 22.5 g (61 mmol),66% of theory, purity according to HPLC 89.4%.

2nd Step:1-[2-(12H-11,12-diazaindeno[2,1-a]fluoren-11-yl)phenyl-sulfanyl]pyrrolidine-2,5-dione

27.3 g (75 mmol) of2-(12H-11,12-diazaindeno[2,1-a]fluoren-11-yl)benzenethiol are added to asolution of 10 g (75 mmol) of NCS in 150 ml of CH₂Cl₂ at 0° C., 10.5 ml(75.3 mmol) of Et₃N are subsequently added, and the mixture is stirredat room temperature for 18 h. The organic phase is dried over MgSO₄, andthe solvent is removed in vacuo. The residue is recrystallised fromacetone and finally sublimed in a high vacuum. Yield: 30 g (66 mmol),85% of theory, purity according to HPLC 88.3%.

3rd Step: Cyclisation

A solution of 4.6 g (10 mmol) of1-[2-(12H-11,12-diazaindeno[2,1-a]-fluoren-11-yl)phenylsulfanyl]pyrrolidine-2,5-dionein 40 ml of CH₂Cl₂ is added to a solution of 0.9 g (5 mmol) ofN,N-dimethyltryptamine, 0.2 g (0.5 mmol) of tetrabutylammoniumhydrogensulfate and 5 ml of 50% KOH solution in 25 ml of CH₂Cl₂, and themixture is stirred at room temperature for 3 h. 0.2 g (0.5 mmol) oftetrabutylammonium hydrogensulfate is subsequently again added, and themixture is stirred for a further 3 h. The organic phase is dried overMgSO₄, and the solvent is removed in vacuo. The residue isrecrystallised from acetone and finally sublimed in a high vacuum.Yield: 2.4 g (6.5 mmol), 66% of theory, purity according to HPLC 99.9%.

Example 9

1st Step: methyl 2-(9H-carbazol-1-ylamino)benzoate

35.51 g (234.9 mmol) of methyl anthranilate are dissolved in 500 ml oftoluene and degassed well. 52 g (213 mmol) of 1-bromocarbazole, 2.1 g(10.7 mmol) of 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene, 1.19 g(5.34 mmol) of Pd(OAc)₂ and 76.5 g (234.9 mmol) of Cs₂CO₃ are added, andthe mixture is then degassed and stirred at 100° C. under aprotective-gas atmosphere for 24 h. The solids are subsequently filteredoff via Celite, and the organic phase is washed with water, dried overMgSO₄ and evaporated. The crude product is washed by stirring with hotheptane, giving 57.4 g (108 mmol), 86% of theory, purity according toHPLC 86%.

2nd Step: 2-[2-(9H-carbazol-1-ylamino)phenyl]propan-2-ol

71.7 g (227 mmol) of methyl 2-(9H-carbazol-1-ylamino)benzoate areinitially introduced in 2000 ml of THF under protective gas and cooledto 0° C. 300 ml of 2 M methylmagnesium chloride solution are addeddropwise at this temperature, and the mixture is subsequently brought toroom temperature overnight. 600 ml of saturated NH₄Cl solution and 900ml of water/conc. HCl 8:1 are added to the solution. The phases areseparated, and the solvent is removed in vacuo. The content of productaccording to ¹H-NMR is about 90% with an overall yield of 64.5 g (90%).

3rd Step: 7,7-dimethyl-12,13-dihydro-7H-indolo[3,2-c]acrdine

63 g (200 mmol) of 2-[2-(9H-carbazol-1-ylamino)phenyl]propan-2-ol areinitially introduced in 268 g (2734 mmol) of polyphosphoric acid underprotective gas and cooled to 0′C. The mixture is subsequently stirred at100° C. for 3 h and then cooled to room temperature. Water is added tothe mixture with ice cooling, the mixture is extracted with ethylacetate, and the solvent is removed in vacuo. The content of productaccording to ¹H-NMR is about 96% with an overall yield of 53 g (90%).

4th Step: Cyclisation

43 g (145 mmol) of 7,7-dimethyl-12,13-dihydro-7H-indolo[3,2-c]acridineare added to 23 ml (159.5 mmol) of methyl 2-iodobenzoate in 150 ml ofdi-n-butyl ether, and the solution is degassed. 10 g (0.158 mmol) ofcopper powder, 1.38 g (0.007 mmol) of copper(I) iodide and 22 g (159.6mmol) of K₂CO₃ are subsequently added to the mixture, which is thenstirred at 144° C. under protective gas for 4 days. The organic phase isdried over MgSO₄, and the solvent is removed in vacuo. The residue isrecrystallised from acetone and finally sublimed in a high vacuum.Yield: 19.5 g (49 mmol), 34% of theory, purity according to HPLC 99.9%.

Example 10

1st Step:3-[(Z)-1-eth-(E)-ylidenepenta-2,4-dienyl]-8-phenyl-11,12-dihydro-11,12-diazaindeno[2,1-a]fluorene

13.3 g (110.0 mmol) of phenylboronic acid, 20 g (50 mmol) of3,8-dibromo-11,12-dihydroindolo[2,3-a]carbazole and 44.6 g (210.0 mmol)of tripotassium phosphate are suspended in 500 ml of toluene, 500 ml ofdioxane and 500 ml of water. 913 mg (3.0 mmol) of tri-o-tolylphosphineand then 112 mg (0.5 mmol) of palladium(II) acetate are added to thissuspension, and the reaction mixture is heated under reflux for 16 h.After cooling, the organic phase is separated off, filtered throughsilica gel, washed three times with 200 ml of water and subsequentlyevaporated to dryness. The residue is recrystallised from toluene andfrom dichloromethane/isopropanol. The yield is 16 g (39 mmol),corresponding to 80% of theory.

2nd Step:(2-bromophenyl)-(3,8-diphenyl-12H-11,12-diazaindeno[2,1-a]fluoren-11-yl)methanone

2.1 g (52.5 mmol) of NaH (60% in mineral oil) are dissolved in 500 ml ofTHF under a protective atmosphere. 20 g (50 mmol) of3-[(Z)-1-eth-(E)-ylidenepenta-2,4-dienyl]-8-phenyl-11,12-dihydro-11,12-diazaindeno[2,1-a]-fluoreneand 11.5 g (52.5 mmol) of 15-crown-5 dissolved in 200 ml of THF areadded. After 1 h at room temperature, a solution of 12 g (55 mmol) of2-bromobenzoyl chloride in 250 ml of THF is added dropwise. The reactionmixture is stirred at room temperature for 18 h. After this time, thereaction mixture is poured onto ice and extracted three times withdichloromethane.

The combined organic phases are dried over Na₂SO₄ and evaporated. Theresidue is extracted with hot toluene and recrystallised fromtoluene/n-heptane. The yield is 22 g (75%).

3rd step

150 ml of di-n-butyl ether are added to 85 g (145 mmol) of(2-bromophenyl)-(3,8-diphenyl-12H-11,12-diazaindeno[2,1-a]fluoren-11-yl)methanone,and the solution is degassed. 10 g (158 mmol) of copper powder, 1.38 g(7 mmol) of copper(I) iodide and 22 g (159.6 mmol) of K₂CO₃ aresubsequently added to the mixture, which is then stirred at 144° C.under protective gas for 4 days. The organic phase is dried over MgSO₄,and the solvent is removed in vacuo. The residue is recrystallised fromacetone and finally sublimed in a high vacuum. Yield: 63 g (124 mmol),86% of theory, purity according to HPLC 99.9%.

Example 11 Production of OLEDs

OLEDs according to the invention and OLEDs in accordance with the priorart are produced by a general process in accordance with WO 2004/058911,which is adapted to the circumstances described here (layer-thicknessvariation, materials).

The data for various OLEDs are presented in the following ExamplesI1-I10 (see Tables 1 and 2). Glass plates coated with structured ITO(Indium tin oxide) in a thickness of 150 nm are coated with 20 nm ofPEDOT (poly(3,4-ethylenedioxy-2,5-thiophene), spin-coated from water;purchased from H. C. Starck, Goslar, Germany) for improved processing.These coated glass plates form the substrates to which the OLEDs areapplied. The OLEDs have in principle the following layer structure:substrate/hole-transport layer (HTL)/interlayer (IL)/electron-blockinglayer (EBL)/emission layer (EML)/electron-transport layer (ETL)/optionalelectron-injection layer (EIL) and finally a cathode. The cathode isformed by an aluminum layer with a thickness of 100 nm. The precisestructure of the OLEDs is shown in Table 1. The materials used for theproduction of the OLEDs are shown in Table 3.

All materials are applied by thermal vapour deposition in a vacuumchamber. The emission layer here always consists of at least one matrixmaterial (host material) and an emitting dopant (emitter), which isadmixed with the matrix material or materials in a certain proportion byvolume by co-evaporation. An expression such as M1:TEG1 (95%:5%) heremeans that material M1 is present in the layer in a proportion by volumeof 95% and TEG1 is present in the layer in a proportion of 5%.Analogously, the electron-transport layer may also consist of a mixtureof two materials.

The OLEDs are characterised by standard methods. For this purpose, theelectroluminescence spectra, the current efficiency (measured in cd/A),the power efficiency (measured in lm/W) and the external quantumefficiency (EQE, measured in percent) as a function of the luminousdensity, calculated from current/voltage/luminous density characteristiclines (IUL characteristic lines), and the lifetime are determined. Theelectroluminescence spectra are determined at a luminous density of 1000cd/m², and the CIE 1931 x and y colour coordinates are calculatedtherefrom. The expression U1000 in Table 2 denotes the voltage requiredfor a luminous density of 1000 cd/m². SE1000 and LE1000 denote thecurrent and power efficiencies achieved at 1000 cd/m². Finally, EQE1000is the external quantum efficiency at an operating luminous density of1000 cd/m.

The data for the various OLEDs are summarised in Table 2.

Some of the examples are explained in greater detail below. However, itshould be pointed out that this only represents a selection of the datashown in Table 2.

Use of Compounds According to the Invention as Matrix Materials inPhosphorescent OLEDs

On use of materials according to the invention as matrix forphosphorescent emitters, good voltages and in some cases very goodefficiencies are obtained. In particular, materials M1 and M2 aredistinguished by the fact that very high current efficiencies (62 cd/A,17.1% EQE) are achieved for low emitter concentrations of 5% (ExamplesI1 and I2). This is not the case for a large number of conventionalmatrix materials and is advantageous from a technical point of viewsince the iridium complexes often employed as emitter are notsufficiently thermally stable for mass production with short tact times.The use of a relatively low emitter concentration allows lowervapour-deposition temperatures for the same tact time, enabling theproblem of the thermal stability to be avoided. On operation at constantcurrent, the luminous density of Examples I1 and I2 drops from aninitial value of 8000 cd/m² to 6400 cd/m² after about 90 h. Furthermaterials according to the invention likewise exhibit good performancedata, as revealed by Table 2.

Use of Compounds According to the Invention as Electron-TransportMaterials

The compounds according to the invention can furthermore be employed inthe electron-transport layer of OLEDs. On combination of material ETM1according to the invention with LiQ as electron-injection layer, avoltage of 4.7 V, a current efficiency of 51 cd/A and thus a good powerefficiency of 35 lm/W are obtained for a green-phosphorescent OLED(Example I9).

TABLE 1 Structure of the OLEDs HTL IL EBL EML ETL EIL Ex. ThicknessThickness Thickness Thickness Thickness Thickness I1 SpA1 70 nm HATCNBPA1 M1:TEG1 ST1:LiQ (50%:50%) — 5 nm 90 nm (95%:5%) 30 nm 30 nm I2 SpA170 nm HATCN BPA1 M2:TEG1 ST1:LiQ (50%:50%) — 5 nm 90 nm (95%:5%) 30 nm30 nm I3 SpA1 70 nm HATCN BPA1 M3:TER1 ST1:LiQ (50%:50%) — 5 nm 90 nm(85%:15%) 30 nm 30 nm I4 SpA1 70 nm HATCN BPA1 M4:TER1 ST1:LiQ (50%:50%)— 5 nm 90 nm (85%:15%) 30 nm 30 nm I5 SpA1 70 nm HATCN BPA1 M5:TEG1ST1:LiQ (50%:50%) — 5 nm 90 nm (90%:10%) 30 nm 30 nm I6 SpA1 70 nm HATCNBPA1 M6:TEG1 ST1:LiQ (50%:50%) — 5 nm 90 nm (90%:10%) 30 nm 30 nm I7SpA1 70 nm HATCN BPA1 M7:TEG1 ST1:LiQ (50%:50%) — 5 nm 90 nm (90%:10%)30 nm 30 nm I8 SpA1 70 nm HATCN BPA1 M8:TEG1 ST1:LiQ (50%:50%) — 5 nm 90nm (90%:10%) 30 nm 30 nm I9 SpA1 70 nm HATCN BPA1 IC1:TEG1 ETM1 LiQ 5 nm90 nm (90%:10%) 30 nm 30 nm 3 nm I10 SpA1 70 nm HATCN BPA1 M9:TEG1ST1:LiQ (50%:50%) — 5 nm 90 nm (90%:10%) 30 nm 30 nm

TABLE 2 Data for the OLEDs U1000 SE1000 LE1000 EQE CIE x/y at Ex. (V)(cd/A) (lm/W) 1000 1000 cd/m² I1 3.7 62 54 17.1% 0.34/0.62 I2 3.8 59 4916.2% 0.35/0.61 I3 4.6 6.1 4.2 9.1% 0.69/0.31 I4 4.3 5.8 4.2 8.6%0.69/0.31 I5 5.1 34 21 9.2% 0.35/0.61 I6 3.9 54 44 15.3% 0.36/0.61 I75.1 44 27 12.1% 0.37/0.60 I8 3.8 48 40 13.2% 0.37/0.60 I9 4.7 51 3513.9% 0.35/0.61 I10 3.7 52 50 14.7% 0.36/0.61

TABLE 3 Structural formulae of the materials for the OLEDs

HATCN

SpA1

BPA1

ST1

TER1

TEG1

IC1

M1 (according to the invention)

M2 (according to the invention)

M3 (according to the invention)

ETM1 (according to the invention)

M4 (according to the invention)

M5 (according to the invention)

M6 (according to the invention)

M7 (according to the invention)

M8 (according to the invention)

LiQ

M9 (according to the invention)

The invention claimed is:
 1. An electronic device comprising a compound of the formula (1)

where the following applies to the symbols and indices used: X is C═O, C(R)₂, O, S, C═S, SO or SO₂; Y is C; W is on each occurrence, identically or differently, CR or N, with the proviso that not more than three groups W in a ring stand for N, and with the further proviso that W═C if a group E is bonded to this group W; Z is, identically or differently on each occurrence, CR or N; or two adjacent groups Z stand for a group of the formula (2)

in which the dashed bonds indicate the linking of this unit; E is, identically or differently on each occurrence, a single bond, C(R)₂, NR, O, S, C═O, C═S, C═NR, C═C(R)₂, Si(R)₂, BR, PR, P(═O)R, SO or SO₂; Ar is a group of one of the following formulae (7), (8), (9) or (10):

wherein the dashed bond indicates the link to N, # indicates the position of the link to X, * indicates the position of the link to E if a group E is present, and W and V stands for NR, O or S, wherein W is equal to C if a group E is bonded at this position; and wherein a maximum of one symbol W per ring stands for N and the remaining symbols W per ring stand for CR; A is R if m=n=0, and is an aryl or heteroaryl group having 5 to 30 aromatic ring atoms, which may in each case be substituted by R, or a group —CR═CR—, —CR═N— or —N═N— if an index m or n=1 and the other index m or n=0, or is an aryl or heteroaryl group having 5 to 30 aromatic ring atoms, which may in each case be substituted by R, if the indices m=n=1; R is selected on each occurrence, identically or differently, from H, D, F, Cl, Br, I, CN, NO₂, N(Ar¹)₂, N(R¹)₂, C(═O)Ar¹, P(═O)(Ar¹)₂, a straight-chain alkyl or thioalkyl group having 1 to 40 C atoms or a branched or cyclic alkyl or thioalkyl group having 3 to 40 C atoms or an alkenyl or alkynyl group having 2 to 40 C atoms, each of which is optionally substituted by one or more radicals R¹, where one or more non-adjacent CH₂ groups is optionally replaced by R¹C═CR¹, C≡C, Si(R¹)₂, Ge(R¹)₂, Sn(R¹)₂, C═O, C═S, C═Se, C═NR¹, P(═O)(R¹), SO, SO₂, NR¹, O, S or CONR¹ and where one or more H atoms is optionally replaced by D, F, Cl, Br, I, CN or NO₂, an aromatic or heteroaromatic ring system having 5 to 80 aromatic ring atoms, which is optionally in each case be substituted by one or more radicals R¹, an aryloxy or heteroaryloxy group having 5 to 60 aromatic ring atoms, which is optionally substituted by one or more radicals R¹, or a combination of these systems, where two or more adjacent substituents R may optionally form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system, which is optionally substituted by one or more radicals R¹; R¹ is selected on each occurrence, identically or differently, is H, D, F, Cl, Br, I, CN, NO₂, N(Ar¹)₂, N(R²)₂, C(═O)Ar, C(═O)R², P(═O)(Ar¹)₂, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40 C atoms or a branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 C atoms or an alkenyl or alkynyl group having 2 to 40 C atoms, each of which is optionally substituted by one or more radicals R², where one or more non-adjacent CH₂ groups is optionally replaced by R²C═CR², C≡C, Si(R²)₂, Ge(R²)₂, Sn(R²)₂, C═O, C═S, C═Se, C═NR², P(═O)(R²), SO, SO₂, NR², O, S or CONR² and where one or more H atoms is optionally replaced by D, F, Cl, Br, I, CN or NO₂, an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which is optionally in each case be substituted by one or more radicals R², an aryloxy or heteroaryloxy group having 5 to 60 aromatic ring atoms, which is optionally substituted by one or more radicals R², or a combination of these systems, where two or more adjacent substituents R may optionally form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system, which is optionally substituted by one or more radicals R²; R² is selected from the group consisting of H, D, F, CN, an aliphatic hydrocarbon radical having 1 to 20 C atoms, an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms, in which one or more H atoms is optionally replaced by D, F, Cl, Br, I or CN, where two or more adjacent substituents R² may form a mono- or polycyclic, aliphatic, aromatic or heteroaromatic ring system with one another; Ar¹ is on each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5-30 aromatic ring atoms, which is optionally substituted by one or more non-aromatic radicals R²; two radicals Ar¹ which are bonded to the same N atom or P atom may also be bridged to one another here by a single bond or a bridge selected from N(R²), C(R²)₂ or O; m is 0; n is 0 or 1, where, for n=0, a group R instead of the group E is bonded to A; p is 1; wherein said heteroaryl groups and heteroaromatic ring systems contain at least one heteroatom selected from the group consisting of N, O, and S.
 2. The electronic device according to claim 1, wherein in the compound of the formula (1) E stands, identically or differently on each occurrence, for a single bond, CR₂, C═O, NR, O or S.
 3. The electronic device according to claim 1, wherein in the compound of the formula (1) A stands for a group of one of the following formulae (3), (4), (5) or (6):

where the dashed bond indicates the link to N, * indicates the position of the link E if a group E is present, W has the meaning given in claim 1, and W is equal to C if a group E is bonded at this position, and V stands for NR, O or S.
 4. The electronic device according to claim 1, wherein in the compound of the formula (1) the following applies to the symbols and indices used: X is C═O, CR₂, S, O or SO₂; E is, identically or differently on each occurrence, a single bond, CR₂, C═O, NR, O or S; A is an aryl or heteroaryl group having 5 to 16 aromatic ring atoms, which may in each case be substituted by one or more radicals R, or a group —CR═CR—, —CR═N— or —N═N—; Z═Z in the five-membered ring stands for a group of the formula (2) defined in claim 1; Ar stands for a group of one of the following formulae (7) to (10):

where the dashed bond indicates the link to N, # indicates the position of the link to X, * indicates the position of the link to E if a group E is present, and W has the meaning given in claim 1; W here is equal to C if a group E is bonded at this position; furthermore, V stands for NR, O, S or CR₂; m is 0; and n is
 1. 5. The electronic device according to claim 1, wherein the compound of the formula (1) is selected from the compounds of the following formulae (11) to (37):

where the symbols used have the meanings given in claim
 1. 6. The electronic device according to claim 1, wherein the compound of the formula (1) is selected from the compounds of the following formulae (11a) to (37a):

where the symbols used have the meanings given in claim
 1. 7. The electronic device according to claim 1, wherein the compound of the formula (1) is selected from the compounds of the following formulae (11b) to (37b):

where the symbols used have the meanings given in claim
 1. 8. The electronic device according to claim 5, wherein in the compound of the formula (1) X stands for C═O or SO₂ and E stands for CR₂, C═O or NR.
 9. The electronic device according to claim 1, wherein in the compound of the formula (1) R is selected, identically or differently on each occurrence, from H, D, F, Cl, Br, CN, N(Ar¹)₂, C(═O)Ar¹, a straight-chain alkyl group having 1 to 10 C atoms or a branched or cyclic alkyl group having 3 to 10 C atoms or an alkenyl or alkynyl group having 2 to 10 C atoms, each of which is optionally substituted by one or more radicals R¹, where one or more non-adjacent CH₂ groups is optionally replaced by O and wherein one or more H atoms is optionally replaced by D or F, an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms, which may in each case be substituted by one or more radicals R¹, an aryloxy or heteroaryloxy group having 5 to 30 aromatic ring atoms, which is optionally substituted by one or more radicals R¹, or a combination of these systems.
 10. The electronic device according to claim 1, wherein the device is an organic electroluminescent device (OLED), an organic integrated circuit (O-IC), an organic field-effect transistor (O-FET), an organic thin-film transistor (O-TFT), an organic light-emitting transistor (O-LET), an organic solar cell (O-SC), an organic optical detector, an organic photoreceptor, an organic field-quench device (O-FQD), a light-emitting electrochemical cell (LEC), an organic laser diode (O-laser) or an organic plasmon emitting device.
 11. The organic electroluminescent device according to claim 1, wherein the compound of formula (1) is employed as matrix material for fluorescent or phosphorescent emitters and/or in a hole-blocking layer and/or in an electron-transport layer and/or in an electron-blocking or exciton-blocking layer and/or in a hole-transport layer, or wherein the compound of formula (1) is employed in an optical coupling-out layer. 